1. Technical Field
The present invention relates generally to data transmission in data communication networks, by way of example, the synchronous optical networks, (SONET networks) and Synchronous Digital Hierarchy networks (SDH networks) and more particularly to the control of alarm messages within a network to prevent the excessive generation of alarm messages from degrading network performance.
2. Related Art
New networks and information exchange capabilities that were unimaginable even in recent times are being developed and implemented in a way that impacts businesses and individuals in a significant way. For example, desktop computers may now be integrated with wireless radio telephones to allow the transmission of information from the computer to a destination by way of a land line communication network and then by way of a wireless communication network.
The recent explosion of the internet is creating the capability and desire for networks of all types to be integrated and coupled to exchange data signals carrying varying types of information. In many cases, the same data will be transported through a local area network prior to being delivered to the internet. Thus, by way of example, a digital signal can be transported from a source through a local area network and through the internet to a final destination. Moreover, within the internet portion itself, there may be a need to transport the user data through a backbone data transfer port infrastructure, by way of example, through a fiber optic ring network. The aforementioned SONET and SDH networks play a key role in providing a backbone data transport infrastructure.
Generally speaking, the internet itself is in essence a collection of many large and small computer networks that are coupled together over high speed backbone data links such as T-1, T-3, OC-1 and OC-3. Stated differently, the internet is a network of networks. As a result of the creation of the internet, worldwide access may be achieved. People and their equipment may now communicate from most any civilized point to another in a fast and relatively inexpensive medium.
In order to make communication devices created by companies throughout the world compatible with each other to create local area networks and worldwide networks such as the internet protocols and standards are often defined. These protocols and standards are used to guide the design of the communication devices, and more specifically, to guide the design of the operating logic in software within the devices. While communication devices that are designed in view of these standards do not always follow the suggested models exactly, they are usually compatible with the protocol-defined interfaces (physical and logical).
Regarding its physical aspects, the internet is a packet switched network that is currently based on a group of protocols for exchanging data. For example, a transmission control protocol/internet protocol (TCP/IP) is a connection-oriented protocol that first establishes connection between two computer systems that are to exchange data. The digital information is then broken into data packets having a defined format. The packets are attached to headers that are for containing control and address information and are transmitted through the internet and through the back hall infrastructures.
Many of the common backbone data transport systems utilized include time division multiplexed (TDM) double ring transmission systems. Double ring TDM systems are generally known, especially for fiber optic communication networks. In order to maintain transmission in the event of a fault on one of the channels of the communication links, it is typically common to find ring transmission systems in which transmissions occur in two directions. Specifically, transmissions occur in one direction through all of the nodes in the ring in a working path in through an opposite direction in a protection path.
The protection path is, traditionally, a redundant path for transmitting signals in a failure condition. Examples of fiber optic TDM systems include the SONET and SDH double ring fiber optic communication systems used in North American and Europe, respectively. As a result of the internet, many types of networks that traditionally have been independent of one another are now being integrated so that a user of one type of device may relay messages to another type of device.
By way of example, networks are being integrated to allow a user of a computer to generate a message that is transmitted to a recipient's cellular phone. By way of example, the sender might enter a message upon his computer, then use the public switch telephone network to access the internet wherein the message is transmitted to a paging company that in turn utilizes a cellular network to deliver a text message to the recipient.
In the described example, three different networks were utilized to deliver the message. The internet formed the backbone network that tied the public switched telephone network to the wireless network to deliver the message. Moreover, had that user been on a computer terminal that is part of a corporate LAN, by way of example, then the message would have had to be transmitted through the corporate LAN prior to being transmitted over the public switch telephone network and then the internet and then the wireless network.
Because the internet and demand for internet access has exploded, the aforementioned data transport networks for providing a data backhauling have been developed to conduct large numbers of communication channels and large amounts of data. Fiber optic networks, in particular, are very attractive for backhauling data because they have achieved very high capacity rates. One fiber optic strand alone can carry dozens of times more data than a traditional wire line. Because a fiber optic cable comprises a bundle of many such strands, the data throughput capacity of modem fiber optic networks is enormous.
As these networks evolve and progress, the control of the networks is developed at many different layers or levels of abstraction. For example, the OSI model defines seven (7) layers of protocol for data transport and control of the same. Needless to say, the software and systems that are required to merely control such large amounts of data form their own networks that are also very sophisticated and have significant feedback mechanisms to enable precise control.
For one example, an element management system may receive feedback on network conditions from up to 250 cross connect systems that are used for routing and controlling data flow. Each of the 250 cross connect systems, in turn, may control up to 8,000 logical communication lines in a data pipeline network. Thus, significant amounts of error messages may be generated when a problem is detected by one of the 250 cross connect devices.
More specifically, network management systems can operate under degraded conditions or even crash when an event occurs that causes at least one network element to generate large numbers of messages, alarms and other signals to the event. The results from a surge of alarms (hereinafter event flow) may lead to problems ranging from system degradation to actual system crash. What is needed therefore is a system and method for preventing an event flow from degrading or crashing the system or network.